Capivasertib-induced diabetic ketoacidosis in a patient with stage IV breast cancer: A case report

Purpose Capivasertib is a selective pan–protein kinase B (AKT) inhibitor for hormone receptor–positive breast cancer. Cellular phosphoinositide 3-kinase and AKT activity plays an important role in glucose homeostasis. Additionally, AKT has a role in regulating hepatic glycogenolysis and glucose uptake via glycogen synthase kinase-3. Previous studies have found the incidence of hyperglycemia with capivasertib to be 13% to 49%. Summary We report the case of a 74-year-old female with capivasertib-associated diabetic ketoacidosis (DKA) with evidence of extreme insulin resistance. The patient was started on capivasertib for stage IV breast cancer and experienced hyperglycemia 8 days after resuming the medication. Her initial blood glucose level was 632 mg/dL, with an anion gap of 29 mEq/L and a pH of 7.22. She was managed according to the institution’s DKA protocol with a peak insulin infusion rate of 130 units/h (1.76 units/kg/h). The patient’s blood glucose level improved after 40 hours on the continuous insulin drip, and she was discharged after 10 days with a prescription for sliding scale insulin and the instruction to discontinue capivasertib. Conclusion This case report provides evidence of extreme insulin resistance in a patient treated with capivasertib. Guidance on the management of acute hyperglycemia secondary to capivasertib is not currently established, and further research on optimal management of these acute crises is needed.